Double side skinning



United States Patent [72] Inventors Victor W. Krause [56] References Cited Rockford; UNITED STATES PATENTS Mich- 926,825 1/1909 Perkins 1 69/44 W" 1,714,886 5/1929 O'Connor... 146/130 1 1 FM 1,865,542 7/1932 Schettler 69/44 [45] Patented Dec- 29,1970 3,299,926 1/1967 Broersma et a1. 146/241 [73] Ass1gnee Wolverine World Wide, lnc.

Rockford, Mich. Primary Exmniner-Wdhe G. Abercrornble -.3 Michigan Attorney-Price, Heneveld, l-luizenga and Cooper ABSTRACT: This specification describes a method and aparatus for skinnin double animal sides, articular] double [54] DOUBLE SIDE SKINNING ogsides, involving the use of a feed-in plgte having an edge Cums Drawing Fits over which the double side is folded. a cooperative pair of [52] 11.8. CI. 146/241, spaced skinning blades. and a pair of spaced pressing devices,

146/130 each pair being arranged in mirror image fashion with ele- [51 Int. A22c 17/12 ments on opposite sides of the plate, and drive means to cause 50] Field of Search 146/130, relative advancement of the plate with respect to and between 241; 69/44, 37 the devices and blades for simultaneous skinning of both sides.

' PAIEN En-nmmm SHEET '4 BF 5 FIGJL 5 w My m I BY gmy 4. #4 34 FIG. l2.

DOUBLE sum SKINNING BACKGROUND OF'Tl-IE INVENTION This invention relates toskinning of animal sides, and more particularly to a method and apparatus of skinning double hogsides to separate the skin from the attached meat and fatty tissue.

This invention was primarily developed for, and has particular significance relative to the skinning of hogsides. Therefore, it will be largely explained relative thereto, although it is conceivable that the invention in its broadest aspects could be employed for other animals.

The commercial skinning of hogs involves the separation of the skin from the attached meat and fatty tissue in a mariner that the skin will be fully useful for leather goods and the meat and fatty tissue useful largely as high priced bacon except for an inferior portion of the fat back which is suitable only for sausage or the like. Until relatively recently, commercial skinning of hogsides performed with the intention of using both the meat and the skin. involved the slicing of the skin from the attached meat and fatty tissue of two separate single" hogsides for each hog. Each singlefhogside to be skinned had the major meats cuts and the bones already removed, so that it constituted a slab with a teat sti'ip on one edge and a back bone or fat back" region on the opposite edge. The fat back edge was clamped onto a rotational drum periphery and pulled past a skinning blade by rotating the drum.

More recently, employees of the assignee herein developed unique double side butchering and skinning methods and apparatus that enable more effective use of the hogside skin as leather because of the larger area of skin chunk so obtained. With this technique, the slab constitutes the skin and attached meat and fatty tissue of both sides of the hog (hence the term double side), with teat strips on both opposite edges due to the hog having been sliced the length of the belly but not in the back. To skin thisdouble" hogside, i.e. to slice the meat and fatty tissue from the skin, one belly edge or teat strip is grasped in a clamp of a drum, and the double side pulled past the skinning blade .with drum rotation. Although this technique has many advantages, works very effectively, and is in wide commercial usage, close study indicates certain disadvantages also, a few of which are as follows.

Firstly, because of the high cost of bacon, even the meat at the teat strip where the clamp grips has lately become valuable. Hence, it would be desirable not to damage any of this area with the clamp as is done presently. In clamping the teat strip edge, frequently a substantial clamping bite must be taken to get effective clamping, due to the jagged outline of the edge. Secondly, because the double hogside by nature tapers from a narrower width at both teat strip edges to a greater width at the central fat back or backbone region, as the double side is pulled past the skinning blade, the first half being pulled past the blade is of constantly increasing width until the backbone region passes the blade. Consequently, the tapered edges advancing into the blade are raw edges. It has been found that this condition causes the blade to gouge undesirable pockets into these edges. Thirdly, the heavy rotating drum of the present double side skinning machine must itself be rotationally started and stopped for each slab, thereby requiring substantial accelerating and braking power.

SUMMARY OF THE INVENTION It is an object of this invention to provide a unique approach to double side skinning that eliminates the first, second, and third disadvantages noted above. Neither teat strip edge of the product is clamped to damage any of the skin and/or meat. No pockets are gouged in the product since the skinning blade never faces raw edges. Blade action is always from the wider portions to-the narrower portions. There is no heavy drum to be rotationally started and stopped. Both sides of the double side are skinned simultaneously, rather than consecutively, to enable more rapid operation. Skinning of both sides is done with balanced pressurev roll forces and balanced skinning blade forces, so that no special'bearing structure is required to counteract the pressure roll or blade forces.

The method and apparatus employ a double side support feed plate having one edge which engages the skin surface of the double side, at the backbone region, and over which the double side is folded so that like portions are on opposite sides of the plate, and withthe skin being in contact with the opposite side faces of the plate. This plate is power driven, to

cooperate with a pair of opposing, plate straddling, pressure applying means to hold the side portions against the plate faces, and with a pair of blades. spaced astraddle the plate in a manner to simultaneously slice the meat and fatty tissue from the skin on both sides of the plate as relative movement occurs between the plate and blades.

The preferred embodiments of the invention involve additional features described specifically herein. Additional advantages and objects will be apparent from the specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of one form of the novel apparatus;

FIG. 2 is a side elevational view of a drive mechanism for the apparatus in FIG. 1;

FIG. 3 is a top plan view of the structure in FIG. 2;

FIG. 4 is an enlarged fragmentary sectional plan view of the blade assembly of the apparatus;

FIG. 5 is an enlarged side elevational view of the apparatus in FIG. 4; I

FIG. 6 is a fragmentary end elevational view of the apparatus in FIGS. 4 and 5, taken from the right end of the structure as viewed in FIG. 5;

FIG. 7 is a fragmentary plan view of the pressure roller structure of the device;

FIG. 8 is a side elevational sectional view of the apparatus in FIG. 7, taken on section lines VIII-VIII;

FIG. 9 is a sectional view taken on plane IX-IX of FIG. 7;

FIG. 10 is a schematic end elevational view of the basic components of the novel apparatus, with a double hogside in position;

FIG. 11 is a plane view taken on planes XI--)(] of FIG. 10;

FIG. 12 is an end elevational view similar to FIG. 10, but showing the hogside being shifted into the skinning operation;

FIG. 13 is a plan view of a prior art skinning apparatus and method; and

FIG. 14 is an end elevational view of the prior art apparatus and method in FIG. 13.

DESCRIPTION OF THE PREFERRED EMBODIMENT The skinning machine or apparatus 10 is illustrated in FIG. 1 with its major components except that the drive mechanism is illustrated separately in FIG. 2 for clarity. The apparatus includes the basic components of a relatively rigid upright feedin and support plate 12 having a relatively narrow elongated upper edge 12, a pair of skinning blade mechanisms 14a and l4b,(FIGS. l and 10) a pair of pressure roll mechanisms 16a and l6b,and other cooperative structure including a support platform means 18, meat and fatty tissue layer discharge support 22, legs 24 for platform 18, and vertical drive mechanism 26 for pusher plate 12, each explained and described specifically hereinafter.

Plate 12 is the main hogside feed-in component of the assembly. It is mounted to shift from its lowered position illustrated in solid lines in FIG. 2 (and in phantom lines in FIG. 1), to its elevated position illustrated in solid lines in FIG. 1 (and in phantom lines in FIG. 2). This plate may be raised and lowered by a variety of mechanisms, whether mechanical, hydraulic, or otherwise. The mechanism shown in this specific embodiment includes a plurality of screw collars 40 mounted to the ends of plate 12, and which threadably receive a pair of upright parallel power screw shafts 42. These screw shafts have their end axially fixed but rotational in suitable end bearings (not shown) so that, with rotation of the shafts, collars 40 and plate 12 are elevated or lowered depending upon the direction of shaft rotation. These shafts can be rotated by suitable power means. This is shown to include rotational motor 46 which has a pair of sprockets 48 and 50 on its output shaft 52 to drive the respective chains 54 and 56, which in turn engage sprockets 58 and 60 mounted on shafts 42. This plate in its lowered position isgenerally below the level of bisected platform 18, and rises through the elongated slot opening 18' in the center of this platform to advance the double hogside. Plate 12 can be further steadied by guides 20, if desired.

Positioned above platform 18, cooperative with the elevating plate 12, is a pair of plate straddling blade means 14a and 14b. Since means 14b is a mirror image of means 14a, only the latter will be discussed in detail. Specifically, blade assembly 14a includes an elongated horizontally oriented blade element 64 having a sharp lower edge and having an adjacent face parallel with plate 12. The opposite ends of this elongated blade are mounted in inverted L-shaped supports 66 (FIGS. 1 and 4-6) by bolts 67 through vertical slots 69 (FIG. 6). Each blade can be vertically adjusted with bolts 68 projecting through the upper horizontal flange of the brackets into engagement with the back edge of the blade. Each of these L- shaped brackets 66 is mounted with a bias toward plate 12 in a manner that blades 64 will normally be at a particular spaced relationship with respect to each other and the plate as specifically noted hereinafter. This biased but resilient mounting may be achieved by supporting each of brackets 66 on a reciprocable shaft 70 which projects away from the plate and bracket and is mounted in bearings in a sleeve 72. Sleeve 72 in turn is supported within a bonnet 74. This bonnet is supported by a pair of pins 76 that are surrounded by a pair of compression coil springs 78 that abut flanges on bonnet 74 on one end and abut a'fixed mounting plate 80 on the other end through which pins 76 project. The relative position of brackets 66 and thus of blade 64 with respect to the like mirror image components on the opposite side of plate 12 can be adjusted by lock nuts 82 threadably engaged on the outer ends of shaft 70. Thus the position of each blade can be adjusted to a controlled position with respect to the feed plate. For normal operation, they are adjusted such that the spacing between the blades is approximately equal to the thickness of plate 12 plus twice the thickness of the skin of the hogsides to be treated. The blades will be automatically shifted against the bias of the springs, temporarily, to accommodate thicker skin areas. Normally, the skin is thicker at the fat and thinner at the belly, i.e. teat strips. Thus, the blade spacing will be preset for the belly skin thickness and will increases slightly at the fat back. Even in the thinner belly skin regions, some bias should be applied to the blades for optimum operation. Hence, the blade spacing is said to be "approximately" equal to the plate thickness plus twice the skin thickness since it will preferably be slightly smaller to get this bias. This can be readily achieved with minor adjustments of nuts 82 by an operator. This blade spacing could be described in another way as being slightly greater than the plate thickness.

Beneath blades 64, ie generally between these knives and platform 18, is the pair of pressure roll means. These engage the respective parts of the advancing double hogside with sufficient force to flatten progressive hogside portions against the opposite faces of plate 12 prior to engagement of the knives with these respective portions. Each pressure roll assembly 160 or 16b is preferably composed of a plurality of end to end, generally coaxially arranged rolls, e.g. rolls 90 and 92 (FIG. 8). Each roll is rotationally mounted in a U-shaped bracket, e.g. 94 for roll 90 and 99 for roll 92, which in turn is mounted on a pair of pins, 96 and 100 respectively, that extend through a guide bracket 98. As illustrated by the mechanism for roller 92, the rods 100 are secured on their outer ends to a plate 102 which is attached to the outer end of shaft 104 of a fluid cylinder 106. There is one cylinder for each roll, and each is rigidly mounted to support 108. Each roll therefore will apply a variable-controlled fluid biasing force. The pressure rolls are oriented at an acute angle from horizontal of about 30 or so (see FIGS. 1 and 10) to allow the double side to be inserted readily onto platform 18,

The method involved can be visualized most readily from FIGS. 10 through 12. The prior art background can be visualized from FIGS. 13 and 14. Typically, the present double side skinning device includes a cylindrical rotational drum 200 mounted on its axle 204, and having an axially extending slot 206 in its periphery containing clamping means for clamping one teat strip (belly) edge of. the double side to be skinned.

Normally, by using the butchering method set forth in U.S.

Pat. No. 3,255,485, the backbone region R will contain an elongated slit S substantially through the layer L1, but not into layer L2.

In the practice of the novel method illustrated in FIGS. 10 through 12, hogside A is generally laid on the platform 18,

with slit S being aligned along slot 18 in platform 18, with rolle'rs 16a and 16b and blades 14a and 14b being arranged generally astraddle slit S, slot 18', and upper edge 12 of plate 12, but above them. Then plate 12 is elevated from its lowered position so that its upper edge engages the skin surface of the hogside along the backbone area opposite slit S, and, with continued rising, pushes the opposite portions of the double hogside up between the pressure rollers and into engagement with the blades, beginning with the central portions and progressing toward the teat strip edges. The pressure rolls force the progressive portions of the double hogside flat against the side faces of plate 12 (as shown in FIG. 12) so that the skin layer L2 is held tightly against the plate and uniform skinning results as progressive portions of the double hogside engage both knives. The spacing of these knives causes them to sever the meat and fatty tissue layer L1 from the skin layer L2, with the two separate segments of layer L1 being discharged out onto like supports 22 (FIG. 1) on opposite sides of the machine. The skin passes between the blades and the plate. Thus, the blades skin from the relatively wide central area adjacent the backbone toward both belly strip edges which are narrower. Hence, the blade is not exposed to the raw edges as occurs during the first half of the skinning operation in the prior art machine shown in FIG. 13, since the skinning is done from the wider portion to the narrower por tions. Depending upon the width of the upper edge of plate 12, a tiny bit of fat back tissue may remain adjacent the backbone region, but this can be readily removed by the fleshing operation to follow, and such material is not significantly valuable since it is normally suitable only for inexpensive sausage or lard. Additional advantages result also which are set forth in the objects in the preliminary part of this application.

In some instances it may be desirable to employ a supplemental clamping element (or elements) such as elongated bar 13 (FIG. 2) which is vertically shiftably mounted adjacent the upper edge'of plate 12 to press the backbone region of the double side against the plate edge to prevent any slippage of the side during skinning, especially at the end of the operation because of one teat strip being configurated differently than the other to upset the otherwise balanced vertical cutting forces of the blades against the tissues. This element is shiftable with the plate. 7

It is entirely conceivable that the method set forth could be practiced on somewhat different apparatus than that disclosed. Hence, although the method and the apparatus do have a definite relationship, they are distinct in certain respects from each other. It is also conceivable that the apparatus could be modified in various mannerswithout departing from the concept presented. Hence, the invention is intended to be limited only by the scope of the appended claims, and the reasonably equivalent structure and method to' those defined therein.

We claim:

1. A method of skinning double hogsides to separate the skin from the meat and fatty tissue layer, comprising the steps of: providing an elongated feed-in pusher plate; retaining a pair of elongated blade elements spaced from and generally astraddle of an elongated edge of said plate with said blades spaced apart an amount slightly greater than the thickness of said plate; placing said plate edge intoengagement with the skin side of the backbone region of the double hogside, and folding the opposite sides of the double hogside against the opposite sides of said plate'with the skin inward and the meat and fatty tissue outward while advancing said plate edge and the opposite side portions of the skin between and past said blades to slice the attached tissue from the skin.

2. The method in claim 1 wherein progressive portions of the opposite sides of said double side are forcibly pressed flat against said plate prior to advancement past said blades.

3. The method in claim 2 wherein said oppositesides are pressed against said plate by biased rolls.

4. The method in' claim 1 wherein said blade retention step.

blades in one position, and being aligned with the space.

between said blades; said blades being spaced apart an amount which is slightly greater then the thickness of said plate; said plate being shiftable between said blades; and drive means to so shift said plate for advancing said double side in folded condition past said blades, whereby the skin is severed from the meat and fatty tissue thereon.

6. The apparatus in claim 5 including a generally flat, double side support surface generally between said plate and blades, normal to said plate, and having a slot therein for passage of said plate therethrough.

7. The apparatus in claim 5 including opposing pressing means adjacent to said blades but closer to said plate when said plate is in said one position, to press progressive portions of the double side against said plate prior to engagement of said portions with said blades.

8. The apparatus in claim 7 wherein said opposing pressing means include biasing means arranged to bias said pressing means toward the shifting plate while allowing movement of said pressing means against the bias to accommodate thicker areas of the double side.

9. The apparatus in claim 5 wherein said blades include biasing mounting means arranged to bias said blades toward the shifting plate while allowing movement of said blades against the bias to accommodate varying thickness skin areas.

10. The apparatus in claim 5 wherein said plate drive means is a power means which includes a pair of powered rotational screws and a plurality of interfitting screw collars around said screws and mounting said plate.

11. The apparatus in claim 5 wherein said plate is vertically oriented and is shifted upwardly in said shifting movement.

12. The apparatus in claim 5 including shiftable clamp means adjacent said plate edge for clamping the backbone region of the double side to, said plate edge. 

